The White Tower is located 60 m far from the citadel's walls, near the Graft bastion. It is high up on the hill and you'll have to climb some 200 steps up to it. The construction was erected between 1460-1494. It has a semicircular shape and it is 14m high. A wooden staircase spirals up four levels. If you reach the top floor, you won't be deceived by the view over the old town. (source, full article)